While Airbus's official line was the revisions had been introduced to boost payload and range, ­industry sources have speculated there may also have been a need to address weight or performance issues that had emerged with the original design.

Clark said the revisions were implemented without any dialogue: "If they had talked to me, I would have said: '[The improvement is] not good enough'," he added.

Although Emirates has only 20 A350-1000s on order, it had been considering switching its 50 -900 orders to the -1000. However, this is unlikely following the revisions.

"On paper, the old -1000 was hugely economical - it was a 777-300 classic replacement," Clark said. "That's why I talked about ­converting my -900 orders." He added the decision to revamp the A350-1000's engine by incorporating a new core has had an impact on commonality. "I had 70 aircraft with the same engine. I don't have that any more," he said.